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What kinds of express or implied limitations are placed on state legislative and judicial authority? Are some areas of law and policy reserved to the federal government by the Constitution itself? What areas are committed to federal legislative authority as the result of congressional action, such as through preemption? Should individual states be allowed to assert extrajudicial authority over issues of national or global concern, potentially imposing burdens on other states or interfering with federal prerogatives to set policy, including by balancing costs and benefits of regulatory action?
These and related questions will be before the U.S. Supreme Court as it begins its October 2026 Term with oral arguments in Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County, scheduled for October 5, 2026.
While it is indeed a case about the legitimate scope of judicial authority to hear climate change litigation cases, as the questions above indicate, the case is about so much more. In recent years, municipalities, counties, and states have increasingly sought to hold energy companies liable for alleged harms associated with climate change through state-law causes of action, usually premised on novel theories of state public nuisance law, expanded views of state consumer fraud or deception statutes, and similar claims.
In 2011 in American Electric Power v. Connecticut, Justice Ginsburg delivered a unanimous opinion for the U.S. Supreme Court holding that similar claims premised on federal law were displaced by the Clean Air Act and its assertion of federal authority over managing global emissions policy. Now, climate change is back at the Supreme Court for it to consider whether claims premised on state law similarly interfere with federal legislative or constitutional authority such that they should be preempted or otherwise displaced.
Case Background
In 2018, Boulder County and the City of Boulder sued Suncor Energy, ExxonMobil, and other defendants, alleging that the defendants’ production and promotion of fossil fuels, along with alleged misrepresentations regarding climate change, contributed to local harms and increased costs associated with climate adaptation and resiliency efforts.
The defendants argued that the plaintiffs’ claims are preempted by federal law and therefore cannot proceed under state law. In May 2025, the Colorado Supreme Court held that the claims could proceed under state law, rejecting arguments that they are displaced or preempted by federal law, including the Clean Air Act.
When the Court hears oral arguments on October 5, 2026, it will consider the following questions:
- Whether federal law precludes state-law claims seeking relief for injuries allegedly caused by the effects of interstate and international greenhouse-gas emissions on the global climate.
- Whether the Court has statutory and Article III jurisdiction to hear the case.
Our Discussion on the Questions Before the Court
Our expert panel analyzed the merits of the parties’ arguments and the broader implications of the Court’s review for climate change litigation, federalism and the constitutional allocation of state and federal authority, preemption, energy policy, and the future of state-law climate and other novel tort claims.
Case Materials
- Docket
- Brief of petitioners Suncor Energy (U.S.A.) Inc., et al. filed.
- Brief of respondents Cty. Comm’rs of Boulder Cty., et al. filed.
Panelists
Each of our panelists authored or represented parties submitting amicus briefs in this case. Continue scrolling to learn more about our panelists’ backgrounds and for links to their briefs.
If you have any questions about the webinar please contact us at [email protected] or 703-993-8008.